/* FileSaver.js
 * A saveAs() FileSaver implementation.
 * 2013-01-23
 *
 * By Eli Grey, http://eligrey.com
 * License: X11/MIT
 *   See LICENSE.md
 */

/*global self */
/*jslint bitwise: true, regexp: true, confusion: true, es5: true, vars: true, white: true,
  plusplus: true */

/*! @source http://purl.eligrey.com/github/FileSaver.js/blob/master/FileSaver.js */
(function (root) {
  var saveAs = saveAs
    || (navigator.msSaveBlob && navigator.msSaveBlob.bind(navigator))
    || (function (view) {
      "use strict";
      var
        doc = view.document
        // only get URL when necessary in case BlobBuilder.js hasn't overridden it yet
        , get_URL = function () {
          return view.URL || view.webkitURL || view;
        }
        , URL = view.URL || view.webkitURL || view
        , save_link = doc.createElementNS("http://www.w3.org/1999/xhtml", "a")
        , can_use_save_link = "download" in save_link
        , click = function (node) {
          var event = doc.createEvent("MouseEvents");
          event.initMouseEvent(
            "click", true, false, view, 0, 0, 0, 0, 0
            , false, false, false, false, 0, null
          );
          node.dispatchEvent(event);
        }
        , webkit_req_fs = view.webkitRequestFileSystem
        , req_fs = view.requestFileSystem || webkit_req_fs || view.mozRequestFileSystem
        , throw_outside = function (ex) {
          (view.setImmediate || view.setTimeout)(function () {
            throw ex;
          }, 0);
        }
        , force_saveable_type = "application/octet-stream"
        , fs_min_size = 0
        , deletion_queue = []
        , process_deletion_queue = function () {
          var i = deletion_queue.length;
          while (i--) {
            var file = deletion_queue[i];
            if (typeof file === "string") { // file is an object URL
              URL.revokeObjectURL(file);
            } else { // file is a File
              file.remove();
            }
          }
          deletion_queue.length = 0; // clear queue
        }
        , dispatch = function (filesaver, event_types, event) {
          event_types = [].concat(event_types);
          var i = event_types.length;
          while (i--) {
            var listener = filesaver["on" + event_types[i]];
            if (typeof listener === "function") {
              try {
                listener.call(filesaver, event || filesaver);
              } catch (ex) {
                throw_outside(ex);
              }
            }
          }
        }
        , FileSaver = function (blob, name) {
          // First try a.download, then web filesystem, then object URLs
          var
            filesaver = this
            , type = blob.type
            , blob_changed = false
            , object_url
            , target_view
            , get_object_url = function () {
              var object_url = get_URL().createObjectURL(blob);
              deletion_queue.push(object_url);
              return object_url;
            }
            , dispatch_all = function () {
              dispatch(filesaver, "writestart progress write writeend".split(" "));
            }
            // on any filesys errors revert to saving with object URLs
            , fs_error = function () {
              // don't create more object URLs than needed
              if (blob_changed || !object_url) {
                object_url = get_object_url(blob);
              }
              if (target_view) {
                target_view.location.href = object_url;
              } else {
                window.open(object_url, "_blank");
              }
              filesaver.readyState = filesaver.DONE;
              dispatch_all();
            }
            , abortable = function (func) {
              return function () {
                if (filesaver.readyState !== filesaver.DONE) {
                  return func.apply(this, arguments);
                }
              };
            }
            , create_if_not_found = { create: true, exclusive: false }
            , slice
            ;
          filesaver.readyState = filesaver.INIT;
          if (!name) {
            name = "download";
          }
          if (can_use_save_link) {
            object_url = get_object_url(blob);
            save_link.href = object_url;
            save_link.download = name;
            click(save_link);
            filesaver.readyState = filesaver.DONE;
            dispatch_all();
            return;
          }
          // Object and web filesystem URLs have a problem saving in Google Chrome when
          // viewed in a tab, so I force save with application/octet-stream
          // http://code.google.com/p/chromium/issues/detail?id=91158
          if (view.chrome && type && type !== force_saveable_type) {
            slice = blob.slice || blob.webkitSlice;
            blob = slice.call(blob, 0, blob.size, force_saveable_type);
            blob_changed = true;
          }
          // Since I can't be sure that the guessed media type will trigger a download
          // in WebKit, I append .download to the filename.
          // https://bugs.webkit.org/show_bug.cgi?id=65440
          if (webkit_req_fs && name !== "download") {
            name += ".download";
          }
          if (type === force_saveable_type || webkit_req_fs) {
            target_view = view;
          }
          if (!req_fs) {
            fs_error();
            return;
          }
          fs_min_size += blob.size;
          req_fs(view.TEMPORARY, fs_min_size, abortable(function (fs) {
            fs.root.getDirectory("saved", create_if_not_found, abortable(function (dir) {
              var save = function () {
                dir.getFile(name, create_if_not_found, abortable(function (file) {
                  file.createWriter(abortable(function (writer) {
                    writer.onwriteend = function (event) {
                      target_view.location.href = file.toURL();
                      deletion_queue.push(file);
                      filesaver.readyState = filesaver.DONE;
                      dispatch(filesaver, "writeend", event);
                    };
                    writer.onerror = function () {
                      var error = writer.error;
                      if (error.code !== error.ABORT_ERR) {
                        fs_error();
                      }
                    };
                    "writestart progress write abort".split(" ").forEach(function (event) {
                      writer["on" + event] = filesaver["on" + event];
                    });
                    writer.write(blob);
                    filesaver.abort = function () {
                      writer.abort();
                      filesaver.readyState = filesaver.DONE;
                    };
                    filesaver.readyState = filesaver.WRITING;
                  }), fs_error);
                }), fs_error);
              };
              dir.getFile(name, { create: false }, abortable(function (file) {
                // delete file if it already exists
                file.remove();
                save();
              }), abortable(function (ex) {
                if (ex.code === ex.NOT_FOUND_ERR) {
                  save();
                } else {
                  fs_error();
                }
              }));
            }), fs_error);
          }), fs_error);
        }
        , FS_proto = FileSaver.prototype
        , saveAs = function (blob, name) {
          return new FileSaver(blob, name);
        }
        ;
      FS_proto.abort = function () {
        var filesaver = this;
        filesaver.readyState = filesaver.DONE;
        dispatch(filesaver, "abort");
      };
      FS_proto.readyState = FS_proto.INIT = 0;
      FS_proto.WRITING = 1;
      FS_proto.DONE = 2;

      FS_proto.error =
        FS_proto.onwritestart =
        FS_proto.onprogress =
        FS_proto.onwrite =
        FS_proto.onabort =
        FS_proto.onerror =
        FS_proto.onwriteend =
        null;

      view.addEventListener("unload", process_deletion_queue, false);
      return saveAs;
    }(self));

  // module export
  if (typeof define === typeof function () { } && define.amd) { // AMD
    define("saveAs",
      function () {
        return saveAs;
      });
  }
  else if (typeof module !== typeof undefined && module.exports) { // Node
    module.exports = saveAs;
  }
  else {
    root.saveAs = saveAs;
  }
})(this);